Step down converter powers multimode PAs in mobile handsets
1 min read
Maxim Integrated Products has introduced a new step down converter designed to power PA modules in mobile phones. According to the company, the MAX8989 is the industry's first dc to dc converter to support power management for multiple communication protocols and has been optimised to extend battery life and talk time in mobile handsets.
The solution is utilised in Infineon's SMARTi UE2 RF engine platform, which is said to deliver 'unparalleled flexibility' and efficiency to multistandard cellular phone systems. It also integrates a high efficiency switching regulator with a parallel bypass ldo for maximum efficiency under all conditions.
According to Maxim, this approach enables designers to minimise the amount of power dissipated within the PA by regulating the PA's output stage supply voltage. By controlling the PA supply voltage to meet transmission power requirements, designers should be able to extend 2G talk time by up to 25% and 3G talk time by up to 10%.
The integrated ldo serves to smooth the transition between step down regulation and operation in dropout. When in dropout, the ldo becomes a low impedance (85m?) bypass FET, designed to ensure minimal power loss during periods of peak current demand.
The MAX8989 supports up to 2.5A and is fully specified over the -40 to 85°C extended temperature range. It is offered in a compact 1.6 x 1.6mm, 9-bump wlp.
